Eutectic Crystallization Activates Solid‐State Zinc‐Ion Conduction

AbstractSolid‐state zinc (Zn) batteries offer a new candidate for emerging applications sensitive to volume, safety and cost. However, current solid polymeric or ceramic electrolyte structures remain poorly conductive for the divalent Zn2+, especially at room temperature. Constructing a heterogeneous interface which allows Zn2+ percolation is a viable option, but this is rarely involved in multivalent systems. Herein, we construct a solid Zn2+‐ion conductor by inducing crystallization of tailored eutectic liquids formed by organic Zn salts and bipolar ligands. High‐entropy eutectic‐networks weaken the ion‐association and form interfacial Zn2+‐percolated channels on the nucleator surfaces, resulting in a solid crystal with exceptional selectivity for Zn2+ transport (t =0.64) and appreciable Zn2+ conductivity (σ =3.78×10−5 S cm−1 at 30 °C, over 2 orders of magnitude higher than conventional polymers), and finally enabling practical ambient‐temperature Zn/V2O5 metal solid cells. This design principle leveraged by the eutectic solidification affords new insights on the multivalent solid electrochemistry suffering from slow ion migration.